Apparatus for collecting and treating heterogeneous waste materials



Aprll 26, 1966 N. A. Plr-:RsoN 3,248,176

APPARATUS FOR COLLECTING AND TREATING HETEROGENEOUS WASTE MATERIALSOriginal Filed May ll, 1961 3 Sheets-Sheet 1 NaMA/v A. Pff-RMN April 26,1966 N. A'. PIERsoN 3,248,176

APPARATUS FOR COLLECTING AND TREATING HETEROGENEOUS WASTE MATERIALSOriginal Filed May ll, 1961 3 Sheets-Sheet 2 l t a l April 25, 1966 N.A. FIERsoN` 3,248,176

APPARATUS FOR COLLECTING AND TREATING HETEROGENEOUS WASTE MATERIALSOriginal Filed May 1l, 1961 5 Sheets-Sheet 3 DIGEST/ON LL 5 5702A sa mmf INVEAL TOR. A/oeMA/u A. P/.eeso/v ATTOP/VE-Y United States Patent O3,248,176 lAPPARATUS FOR COLLECTING AND TREATING HETEROGENEOUS WASTEMATERIALS 1 Norman A. Pierson, Norman, Okla. q Continuation ofapplication Ser. No. 109,324, May 1v1, 1961. This application Jan. 26,1965, Ser. No. 430,235 21 Claims. (Cl. 232.59.1)

This is a continuation Vot'-'applicant?s co-pending application of the'same title, Serial No. 109,324, filed May 1-1, 1961, Vnowabandoned. i

This invention `relatesto a system for collecting municipal refuse andanalogous Waste materials of a heterogeneous nature, and for treatingsuch materials preparatory to converting them 'to useful products. In amore 'specific aspect, the present invention relates 'to improvements inVa `system for Vcollecting municipal lrefuse and 'adjusting the moisturecontent thereof prior to converting the refuse to useful products.

One of .the problems confronted -in rthe collection and disposal `ofmunicipal refuse is the need for sanitary handling of 'the refuse Ifromthe time it is dumped from `collection trucks at a centrally locateddepository until it is ultimately disposed of. In plants whichlundertake to convert all `or part of the :refuse to useful productssuch 1as compost, methane, and other organic chemicals, it is highlydesirable thatja sanitary and `safe `system be providedforreceivin'grefuse from =the collection trucks and for passing refuse into theprocessing Aplant for further treatment.

Although fairly -high standards of sanitation have been -achieved insome of the refuse-receivingsystems heretofore ,in use, these systemshave usually not provided for the most economic `handling of: the [rawrefuse, .since some 'of the beneficial components of .the refuse havebeen lost in such systems. :For example, in order to prevent the liquidsof the refuse from presenting a situs for the breeding of mosquitoes anddisease germs, the refuse has sometimes Ibeen driedY or its liquidcontent otherwise extracted and these fliquids discarded. Since theliquids so discarded often contain chemicals and organisms which maybeused to good advantage in the subsequent `refuse processing operations,the disposalA of these liquids after they are :removed Vfrom the refuseis 'a wasteful procedure. 4 q n n v With the recent development ofcomposting` plants which may, for the lirst time, economically convertlarge Aquantities of municipal refuse lto Abeneficial compost by theprocess of bacterial decomposition, the moisture content of therefusebeingso convertedV has assumedV a new magnitude of importance.h Thus, inorder to provide conditions conducive to optimum bacterial activity, itis necessary in such composting processes to adjust the moisture contentof the refuse Within a, certain range. To Adate, insofarasl am aware,the means employed for adding water or an aqueous uid to therefuse forthe purpose of adjustingits moisture contentvhave been rather ineicientand have dependedlargely upon the estimating ability of operatingpersonnel. 'Moreoverg moisture content control has been sporadic, or atleast periodical rather than continuous, so that within the periodbetween checks of the moisture content the refuse may easily become toodry or toowet to present the optimum conditions for bacterial activity.

In one of its broader aspects, the present invention provides a systemfor sanitarilyfremoving a substantial quantity of the liquid contentofthe raw refuse as -it is brought to the processing plant, and forusing the `liquids so removed to adjust the moisture content of the'refuse to a level desirable for subsequent composting `by bacterialdecomposition. In Athis manner, the refuse mateice rial is dried topromote sanitation prior to its introduction to the processing plant andthe uids Aremoved from the refuse are -then utilized to bring the refusein the processing plant -to v`the desired moisture content forsubsequentconversion to 'the desired products.

In a more vspecific aspect, the invention provides apparatus foreiciently removing a `large portion of the liquid content ot municipalrefuse-as the refuse 'is received from collection trucks at av4processing plant. The apparatus provides Afor the maintenance yof.maximum cleanliness in and around the area where the refuse is rstreceived, vand around and under the -conveyor and storage -bin's whichare utilized for moving and storing the refuse prior to introducing itinto the processing plant. Novel means are provided for preventing -theoccurrence or spread of Alire which may loriginate in the refuse or .inthe( receiving and conveying equipment.

In another of its aspects, the present invention provides a novel andIhighly' efficient c'ontrol system `for continuously monitoring andcontrolling the moisture contentof refuse vprior to introducing therefuse to vcomposting cells where bacteriological decomposition is to'take place. lThe control system lis -completely automatic in Vitsoperation and is ele'ctive to constantly maintain th'e moisture contentof refuse being fed toY the digestion cells y-between preselectedminimumand maximum values. The moisture'control system is further characterizedin having means integrated in the system for introducing an aqueousinoculant'enriched with beneficial bacteria to the refuse at a 'point inthe processing plant Where the inoculant may be thoroughly mixed withthe refuse before therefuse is Jcharged to the digestion cells.v

In accord-ance with the foregoing discussion,it is an object of -thepresent `invention to provide a system for receiving refuse from refusecollection trucks, and for Conveying the refuse to a raw refuse storageybin in a sanitary manner.

An additional object of the present invention is to provide apparatusfor e'iciently receivingloads of refuse intermittently dumped r,tr-omrefuse collection trucks, fand for moving the refu'se so received intoan accumulator forfstorage prior to introduction into a refuseprocessing plant.

An Iadditional objectrof the invention fis to remove a substantialportion of the liquid -content 'from refuse vreceived from refusecollection trucks, and to Vcollect `the extracted liquids `in 'Ia'storage tank for Asubsequent `use in adjusting vthe .moisture contento-fthe refuse in accordance With the demands of the particular type ofprocessing to be'employed.,

A -further object of the present vinvention is'to provide a System inwhich the liquids are extracted from raw'refuse after it is received -inorder :to prevent the development of a situs for the breeding ofmosquitoes and other vermin. The liquid soextracted issubsequentlyutilized in Iadjustying the moisture content fof the refusefto a desired level for subsequent .processing in 'a compostingoperation.

A urther object of the present inventionfis'to-ei'ciently andeconomically collect loads of refuse :intermittently -durnped from`refuse collection trucks at a .central point of accumulation, fromWhichpont it may lbe subsequently fed in metered amounts into aprefuseprocessing plant. f

An yadditional object of -thepresent invention is to provide fascavenging systemtor maintaining the `cleanliness of the area around andunder a system v-for receiving refuse from-collection trucks lat arefuse processing plant.

V,An Aadditional object of the invention is to provide novel means incombination with-said scavenging system for preventing the occurrenceorl spread of tire in the refuse receiving system.

Yet `another object of the invention is to provide a refuse receivingsystem 'in which liquid and small particulate solid material which iscollected from the refuse may be -conserved and subsequently utilized inprocessing the refuse to produce useful products.

Another object of the invention is to provide means for adding abacteria-enriched inoculum to the refuse preparatory to charging therefuse tothe composting cell.

A further 'object of the invention -is to continuously monitor themoisture content of refuse be-ing charged to a composting cell, land forautomatically adding an aqueous material -to the refuse to keep themoisture content at an optimum level for bacterial activity.

These objects and advantages, and other additional bjects andadvantages, will become apparent and will be better understood byreferring to the following description in conjunction with the attacheddrawings which illustrate my invention.

In the drawings:

FIGURE l is a partially schematic plan Vview of the refuse receivingsystem of the present invention.

FIGURE 2 is a view in section taken along line 2 2 of FIG. l.

FIGURE 3 is a view in section taken along line 3 3 of FIG. l.

FIGURE 4 is a plan view of the wash and scavenging systemof the presentinvention.

FIGURE 5 is a schematicrow diagram illustrating the manner in whichliquid is extracted from the raw refuse when it is received, and thensubsequently added to the refuse for continuously maintaining themoisture content of the refuse at an optimum level for bacteriologicaldecomposition.

FIGURE 6 is a schematic illustration of the novel storage #tank used forstoring liquids to be added to the refuse for controlling the moisturecontent thereof.

Referring now to the drawings in detail, and particularly to FIG. l, areceiving pit 10 is provided into which the refuse carried by municipalrefuse collection trucks may be dumped. A truck apron 11 onto which thetrucks may be backed is located adjacent the receiving pin 10, and abumper rail 12 extends along one-side of the pit 10 slightly above thelevel of the truck apron 11.

A sloping wall 13 is provided at the back of the pit 10 and a slideplate 14 is located at one end of the pit. Both the wall 13 and theslide plate 14 are inclined at -an angle of about sixty degrees to thevertical so that refuse contacting these members will gravitate towardthe -bottom of the pit. The upper edge 14a of .the slide plate 14 ishingedly secured to the w-all of the pit 10 for a purpose hereinafterdescribed.

A conveyor 16 comprising a plurality of spaced slats 18 secured toendless chains (not seen) extends across the bottom of the receiving pit10 and upwardly from lthe receiving pit at an angle of approximatelytwenty-three degrees to the horizontal. An electrical control switch 19-is located adjacent the pit 10 to permit the truck drivers to actuatethe conveyor 16 after they have dumped their loads of refuse. At its end20 located remotely Ifrom the receiving pit 10, the conveyor 16 extendsover a refuse receiving pit 10, the conveyor 16 extends over a lrefuse-receiving chamber 22 in the manner most clearly illustrated in FIG. 3.A conveyor 24 is located in the Ibottom of the refuse receiving chamber22 for moving the refuse accumulated in the receiving chamber 22 into aprocessing plant -for subsequent treatment.

In a Itypical processing plant arrangement, the conveyor 24 in thereceiving chamber 22 first moves the refuse accumulated in the receivingchamber onto a -feed table 26 located inside the processing plant 27.The surface of the feed table 26 which supports the refuse depositedthereon by the conveyor 24 may suitably comprise a reversible belt-typeconveyor so that optional feeding of the refuse to a discard conveyor 28or to a picking table 30 may be facilitated. After certain salvageablecomponents of the Vrefuse have been manually removed therefrom while therefuse is on the picking table 30, the

refuse is then delivered to suitable grinding and mixing 1 apparatus forfurther processing.

As has been previously indicated, it is highly desirable that asubstantial portion of the free liquid entrapped in the raw refuse beremoved therefromprior to accumulaa tion and storage of the refuse at acentral location. Such extraction of liquid is eiciently accomplished inthe refuse receiving system illustrated in FIGS. 1 through 3.

In referring to FIG. 2, it will be noted that when refuse is dumped fromcollection trucks into the receiving pit 10,

the refuse must fall a substantial distance in the pit before 1 strikingthe slatted conveyor 16. In falling, the refuse has an opportunity toturn over one or more times so that water or liquids contained in tincans, cartons and the like will be poured out. slatted conveyor 16 withsufficient impact to break open Moreover, the refuse strikes the ipartially sealed containers which may hold residual fruit juices, milk,water, oils or other liquid materials.

The liquids which are thus separated from the `raw refuse passdownwardly through the slats 18 of the con-` veyor 16 and by this routereach the bottom 32 of the pit 10. As shown in FIG. 3, the bottom 32 ofthe4k pit 10 slopes toward one side of the pit. A sump 34 is located lat the lowest side of the bottom 32 of the pit 10 for re:

ceiving liquids which drain into the bottom of the pit. A suitablescreen 36 covers the sump 34 to prevent the sump i from .becomingclogged by any solid materials which may fall through the slattedconveyor 16 in-to the bottom 32 of the pit 10. In order to clean thescreen 36, the slide` i plate 14 may be pivoted upwardly about itshinged edge 14a to allow access to the screen. The liquids which collectin the sump 34 are pumped by a sump pump 38 through conduit 40 to asuitable liquid storage tank 42 (see FIG. 5), where they remainavailable for subsequent use in adjusting the moisture content of therefuse preparatory to certain refuse processing operations.Alternatively, the sump liquids may be discharged to a sewer throughconduit 41, if desired. The moisture control system of` the presentinvention and t-he manner in which it is operated are described ingreater detail below.

After the raw refuse has been deposited on the slattedy conveyor 16 inthe pit 10, it is moved upwardly by the conveyor toward therefusereceiving chamber 22. The conveyor 16 is inclined at an angle ofabout twenty-three degrees to the horizontal so that the solid portionof the refuse will not slide back down the conveyor into the pit 10, butyet residual liquids in the refuse and on the slats 18 will drain downthrough the conveyor. A plurality of batlle plates 44 are disposedimmediately beneath the inclined portion of the conveyor 16 to catch theliquids which drain through the conveyor. The battle plates 44 areinclined and overlapping, as shown in FIG. 3, so that liquids fallingupon the bale plates drain back into the pit 10.

In order to prevent the coagulation of viscous uids such as syrups, oilsand the like on the baille plates 44 and on the bottom 32 of the pit 10,as well as to maintain generally sanitary conditions around and underthe refuse receiving system, novel washing and scavenging apparatus isprovided for use in conjunction with the refuse receiving system. Thewashing and scavenging apparatus comprises a main water line 46 to whichare connected a series of perforated spray pipes 48. The spray pipes 48are p0-` 50 are arranged along each side of the receiving pit 10` andare perforated or provided with suitable nozzles to directv wash waterdown the bottom 32 of the receiving pit toward the sump 34. There areYalso spray pipes 52 located beneath the refuse receiving chamber 22 forkeeping this area clean and sanitary. Concrete ooring 54 is providedunder all of the refuse receiving system and a plurality of drains 56are located in the flooring sothat when the floor is washed down, alldust, spores andY bacteria which accumulate on the oor are received inthe drains. All of the drains 56 connect to a drain line 58 extendinginto the highest end of the pit so that all of these4 waste materialswill be collected in the sump 34. The washing down and collection ofspores and bacteria in the sump 34 is an important aspect of thisinvention since these organisms can subsequently be beneficiallyutilized to` inoculate the refuse preparatory to a composting process inwhich bacteriological decomposition is the primary reaction. Suchinoculation of the .refuse is vdiscussed in greater detail below.

The manner in Whichliquids collected in the sump 34 may be utilized toadjust the moisture content of the refuse preparatory to furtherprocessing of the refuse is best illustrated in FIG. 5. In the preferredembodiment illustrated, the moisture control system of the invention isshown as it is applied to a typical refuse` composting plant. Ingeneral, such plants have one or more large housings or cells in whichbacterial digestion or decomposition of the refuse is induced andallowed to proceed. Such cells are illustrated schematically in FIG. 5land are designated generally by reference 'character 6 0.

After the raw refuse has been dumped, into thejreceiving pit 10, it iscarried upwardly by the slatted conveyor `16 to the` refuse receivingchamber22. From the-receiving chamber 22, the refuse is passed onto afeed table conveyor 2,6 inside the composting plant.A Normally, therefuse will then be passedvonto a picking table 30 to allow suchsalvageable components as` rags, glass, metals, etc., to be manually orotherwise removed. The refuse then passes onto a conveyor 62 whichcarries it into suitable pulverizing and mixing apparatus 64. In thepulverizing `and mixing apparatus 64, the average particle size of the lwill, of course, vary to some extent according to the type of refusewhich is to be composted, .but in any `composting operation the optimummoisture content range will have been determined by appropriate testsupon typical specimens of refuse which will be subjected to thecomposting operation. j

As has been previously indicated,tthe present invention contemplatescontinuous automatic control of the refuse moisture content utilizing,in large part, liquids which have been extracted or separated from' theraw refuse when it is first brought to the composting plant. The iliquids which lhave been recovered from raw refuse are circulated by thesump pump 38 through the conduit 40I Atinto a liquid storage tank 42.The interior of the storage tank 42 is in communicatoin with a dischargecond-uit 68 which terminates over the refuse being carried into the-pulverizing 4and mixing apparatus 64 upon the conveyor 62. A controlvalve is interposed in the discharge conduit 68 so that the rate'ofintroduction of liquid from the storage tank 42 into the refuse may becontrolled according 'to the degree of closure of the valve. i

manually determined, such as by squeezing a small por- 'tion of therefuse.` The preferred embodiment of 'the invention illustrated in FIG.6, however, contemplates the utilization of an electrical control systemfor automatically controlling the moisture 'content of refuse enteringthe digestion'cells. Thus, two or more sensing electrodes 72 aredisposed atv the entrance of the uppermost or initial digester cell 60ina position for continuously contact-ing 'the' refuse as it enters thedigestion cell. The resistance between the two electrodes 72 constitutesa measure of the moisture content of the lrefuse entering the cell.

The electrodes 72 are connected to a selective control device 74 which.is connected to the control valve 70. The selective control device 74is provided to permit the control valve v70 to be continuously adjusteds'o as to keep the moisture contentof the refuse entering the digestercells within'a 'preselected moisture content range. The desired range ofmoisture content .is set into the selecting control 74 before `thecomposting plant is placed in operation, and the select-ive controldevice 74 then functions in response to` the moisture content sensed .bythe electrodes 72 to open or close the control valve V70 asv is'necessary to maintain the moisture content 'at the desired level. Anysuitable electrical circuitry maybe used for `sensing themoist-urecontent of refuse entering the digester cell 60, and for controlling thedegree of "closure of the valve 70 incorrespondence to such moisturecontent. For example, the meter relay and control circuitry manufacturedby Tipptronic, Inc., of Tipp City, Ohio, may be utilized in conjunctionwith a limited torque motor valve manufactures tiy the 'PhiladelphiaGear works, Inc., or Panaderphia, Pennsylvania, to Vaccomplish thedesired control described above. Suitable electrical circuitry for thistype of control is also `manufactured by the 'Minneapolis- HoneywellCompany, of'Minneapolis', Minnesota.

v The construction of the fluid storage tank 42 is an important ffeature of t`he"`present invention. As Villustrated'in FIG. 6, the'storage tank 42 is provided with a Iiloat valve 76 for closing the inlet78A to the tank when 4afpred'etermined level of Water,A sewage or other'liquid adclitive'lzras4 been reached. A suitable conduit 81 isconnec'ted to the top of the tank 42 to facilitate the introduction ofraw sewage to the tank when desired. A bypass valve 80His opened uponclosure of the oat valve 76 to direct the incoming water or sewagesludge to a sewer system. The tank 42 is also provided with a pop-'ottvalve 82 Ain 'the top thereof which will open in the event excessive gaspressures are created in the tankv10. Such a `pop-oft valve .isnecessary since sewageV sludge in the -tank 10` will frequently,generate an appreciable Aamount of methane. suitable agitator orstirrer 84 is positioned in the lower portion of the tank 42 tocontinuously lmix the contents of the tank, particularly when the tankcontains sewage sludge.

Summary of 'operation of system n To summarize the operation of thesystem for collect- .ing and treating refuse material which i's`disclosedl and discussed hereinbefore, the refuse is initially dumped byrefuse collection trucks .into the receiving pit 10 where it comes torest upon the slatted conveyor 16.V 'A substantial portion lof theliquid content of the 'refuse drarns downwardly through the `slats 18 ofthe conveyor 16 into the bottom 32 of the pit 10- as the refuse 'fallsand when it strikes the conveyor 16 with considerable impact. Anadditional lportion of the entrained liquids drains down through theslats 18 of the conveyor 16r as the refuse 1s moved upwardly upon theinclined portion ofthe conveyor after the truck driver has actuated theconveyor by pressing the starter button 19. 'I'he liquidswhich drainAdown ythrough the slats 18 of the conveyor 16 as the refuse is movedtoward the refuse receiving chamber 22 Afall upon the inclined bailleplates 44. The washing and scavenging system of the invention then comesinto play to wash the liquids Vcollected on the bafe plates 44Vdownwardly into the bottom 3-2 of the receiving pit 10. Any solid orliquid materials which fall upon the cona crete ooring 54 whichunderlies the conveyor 16 and refuse receiving chamber 22 are alsowashed into the receiving pit via the drains 56 and main drain line 58.

After the refuse has been deposited in the refuse ac- Cumulator chamber22, it is moved in metered amounts by the conveyor 24 into the refusecomposting plant. In a typical refuse processing plant, the refuse fromthe refuse receiving chamber 22 may be deposited upon a feed tableconveyor 26. The feed table Conveyor 26 is reversible so that the refusemay be passed onto a selection and discard conveyor 28 or onto a pickingtable 30. From the picking table 30, the refuse is moved onto a conveyor62 which conveys the refuse to the entrance of the pulverizing andmixing apparatus 64. It is during the time that the lrefuse is restingupon the conveyor 62 th-at liquids are added thereto to bring themoisture content of the refuse to the desired level.

In referring to FIG. 5, it will be perceived that water which iscollected in the sump 34 in the bottom 32 of the receiving pit 10 iscirculated by the sump pump 38 through the conduit 40 and into theliquid storage tank 42.y In addition to liquids collected in the sump 34and pumped into the storage tank 42 by the sump pump 38, it will, inmany cases, be desirable to add a material which is rich in beneficialbacteria and fungi to the liquid collected in the storage tank 42. Forthis purpose, a conduit 81 is provided in communication with the storagetank 42 Vto facilitate the introduction of raw sewage enriched withbacteria to the tank (see FIG. 6).

It will be understood from the description of the system as it has beenthus far developed that the concept of collecting and storing theliquids extracted from the raw refuse as it is received permits thebeneficial bacteria and spores contained in such liquid to be conservedand subsequently utilized in such refuse processing operations ascomposting by bacteriological decomposition. Moreover, the bacteriacontent of the liquids which are added to the refuse through thedischarge conduit 68 may be further increased by adding a substantialportion of raw sewage to the contents of the liquid storage tank 42.

In the mixing and pulverizing apparatus 64, the liquids, including theraw sewage, which have been added to the refuse while it is upon theconveyor 62 are thoroughly mixed with the refuse, and the refuse isreduced in particle size to the desired extent. The moistened,pulverized refuse is then passed out of the pulverizing and mixingapparatus 64 and into a suitable elevator 66 for carrying the refuseupwardly into the uppermost digestion cell 60 of a series of verticallyspaced digestion cells. As the moistened, comminuted refuse enters thefirst digestion cell 60, its moisture content is sensed by theelectrodes 72. The selective control device 74 responds to the moisturecontent of the refuse Vas indicated by the electrical resistance ofrefuse between the electrodes 72 to control the degree of closure of thecontrol valve 70. The selective control device 74 may be set to adjustthe valve 70 so that the moisture content of the refuse is alwaysmaintained within a certain pre-determined range.

From the foregoing description, it will be perceived that the presentinvention provides a system for sanitarily receiving raw refuse at arefuse processing plant, and for conserving the liquids which areextracted from such refuse for subsequent beneficial utilization in theprocessing of the refuse to useful products. Highly beneficial bacteriaand fungi are conserved by the system and method employed and, althoughthe system has particular value in its :adaptation to use in a bacterialcomposting plant, the principles which are described may likewise beemployed in other types of refuse processing systems.

Changes in the details of construction of the elements of the presentinvention, as well as variations in the steps of the method employed,will occur to those skilled in the art. Insofar as such changes employonly the use of equivalent elements and structures and do not departfrom the principles of the invention, they are deemed to fall within thescope of the invention as dened by the following claims.

I claim: n

1. In a system for composting refuse, the improvement which comprises:

a pit for receiving vraw refuse;

refuse receiving means elevated above ground level and spacedhorizontally from said pit;

a slatted conveyor extending across the bottom of said pit and upwardlyto -said elevated refuse receiving means;

drain means under said conveyor;

a sump in the bottom of said pit below said slatted conveyor;

liquid delivery pipes positioned under said conveyor between said pitand refuse receiving means for washing into said sump via said drainmeans liquid and solid materials falling through the slats of said con-`veyor;

a storage tank connected to said sump for yreceiving the washingsilowing into said sump;

` a conduit communicating with said storage tank and extending over thepath of refuse discharged from said refuse receiving means; and

valve means in said conduit for controlling the ow of material from saidstorage tank to said refuse whereby the moisture content of said refusemay be regul lated as desired prior to composting the refuse bybacterial decomposition.

2. In a system for composting municipal refuse, the

improvement claimed in claim 1 wherein:

said conveyor extends upwardly from said pit to said refuse receivingmeans at an angle to the horizontal of about twenty-three degrees; and

wherein said washing means comprises baffle plate means under saidconveyor between said pit and refuse receiving means, said bailie platemeans being inclined toward said pit to permit liquid drainage into saidpit; and

a plurality of perforated water supply pipes extending between vsaidconveyor and said baffle plate means l and adjacent the bottom of saidpit for washing drippings, dust, spores, waste materials and the likeinto said sump.

3. In a system for composting municipal refuse, the

improvement claimed in claim 1 wherein:

said valve means comprises a valve in said conduit for controlling thevolume of flow through said conduit; and

electrical control means for automatically controlling q tion forelectrically sensing 4the moisture content of said refuse; and meansconnected between said electrodes and said valve for opening said valvewhen the moisture content of said refuse reaches a preselected minimumvalue, and for closing said valve when the moisture content of saidrefuse reaches a preselected maximum value. 5. In a system forcomposting municipal refuse, the improvement claimed in claim 1 andcharacterized further to include:

a pop-ott valve in said tank for releasing gases generated in said tank;feed conduit means interposed between said sump and said tank fordirecting washings accumulated in said sump into said tank; a bypassconduit connected to said feed conduit means for diverting the ow ofliquid from said sump to a sewer;

19 loat valve v'nieans in said tank-arid i responsive Yto .-the levelofliquid in said f tank Afor interrupting-the' Vow -f-liquidin't'os'aidtankefrm"said=feedfconduitm`ans;

'means for introducingrsewage sludge to-saidtankgand VVmeansforagitating the contents 'ofsaid tank. p

"6. A system for receiving an'dlprocessing municipal refusein'asanitarymannercomprising: y t

apitjfor receiving refuse dumped fromrtruckscarrying lsaid refuse, saidpity having a depth `s'u'ilicicefnt "to yallo'w said Areflisetotun infalling from sidltruck to the bottom ofsaidpit, and to Acausesaidii'efuse toV strike the bot-tom Aof' `said lp'itfwith'an impactv'ofsuiicient .magnitudeY to` break open 4liquidicontaining y portionsofffsaidr4 se; Y 4 A y the groundu and hori'zbntally s'pacedV fromfs'aid'pit;

a slatted conveyor across and substantially Vcovering the bottopaofsaidlpitandextendingupwardly from said pit to said'receivingmeiisstan acuteangle to the horizontal; p j

a- Lsump in the bottom ofvs'aid pit beneath said conveyor;

and

means for 'washing into (said p sump Lliquid 'and C solid materials'falli'ng through the slats of-'said conveyor, "said washing y'meansincluding -`abale positioned below the upwardly extending portion ofsaid slatted conveyor andinclined downwardlytowrd' said pit; and pipeshaving openings therein positioned between said conveyor and said baillefor delivering a liquid to the surface of said baille.

7. A system for receiving and processing municipal refuse as claimed inclaim 6 wherein:

said slatted conveyor extends upwardly from said pit to said receivingmeans at an angle to the horizontal of about twenty-three degrees,whereby maximum liquid drainage from said refuse is obtained withoutpermitting solid refuse to slide down said conveyor toward said pit.

8. A system for receiving and processing municipal refuse as claimed inclaim 6 wherein:

the bottom of said pit is inclined Itoward said sump to allow drainageof liquid in said pit into said sump; and

wherein said washing means comprises baille plate means under saidconveyor between said pit and said receiving means, said baille platemeans being inclined toward said pit to permit liquid drainage into saidpit; and

a p1uralityof perforated water supply pipes extending between saidconveyor and said bale plate means and adjacent the bottom of said pitfor washing drippings, dust, spores, waste material and the like intosaid sump.

9. A system for receiving and processing municipal refuse as claimed inclaim 8 wherein some of the perforations in said water supply pipes areoriented in said pipes to direct water upwardly onto the lower side ofsaid conveyor and through the slats of said conveyor; and the remainderof said perforations are oriented in said pipes to direct water downsaid baille plate means toward said pit.

10. A system for receiving and processing municipal refuse as claimed inclaim 6 and characterized further to include:

means connected to said sump for directing the washings accumulated insaid sump to a storage tank for subsequent usage as inoculation materialin a composting process and, alternately, to a sewer system.

11. A system for receiving and processing municipal refuse as claimed inclaim 6 wherein said pit is comprsed of a plurality of side wallssloping inwardly from the top toward the bottom of said pit at an angleof about sixty degrees to the vertical, whereby said pit has a largeopening at its -top and said refuse is directed l0 Pdwnwardly'ontosaidconveyor by-said sloping side walls.

*Lf-'Afsystem forreceiving and processing -municipal refuse asclaimed-in claims-121 wherein; p

"saidfpitihas :ar-substantially vertical side wall spacedA'horizontallyV from the lower,'feed` end of said conveyor, and pV4'saidssun'rp is-'located'adjacentsaid vertical side wall,

and t v-wherein'one ofrsaidsloping vside wallsV comprises `aatfplatehingedly' connected "at onepof its sides to Ythetopo saidvertical, side Wall and extending downwardly and inwardly from saidhinged connection "over, -said conveyor, whereby access to sai'dfsurnplmaybe had by pivoting-said plate toa'substantially 'vertical'positiona4 p l #13. Afsystem for receiving and V`processing imunicipal refuse asclaimedin'claim and-characterized further -to-include: A, l l frneansforcollecting waste materials containingbenewlicialbactera andsporesaccumulating in 4the area "beneath said receiving means andundersaidbale tplate means, rsaid collecting `*means comprising a.plurality of drain pipes communicating with said rpit and extendingthrough the ground below said kbaffleplateV meansand Vsaid receivingAmeans; and y `funnel-shaped collecting drains, at'the surface of thefgrounds below said baille plate means and Vsaid rev Vceivingmeansconnected -to andconimunic'ating with said drain pipes. L ,Y l y14. In a plant for composting'refuse'of the type' having means forpreliminarily pulverizing and vgrinding the refuse, and cell meansdownstream from said pulverizing and grinding means for containing therefuse during the bacterial decomposition thereof, the improvement whichcomprises:

a source of aqueous duid;

means for receiving raw refuse delivered to 4the plant;

means associated with said refuse receiving means for separating liquidsfrom the refuse as delivered to said plant, said liquid separating meansbeing disposed upstream from said pulverizing means;

irst conduit means for conveying said separated liquids to said -sourceof aqueous fluid for addition yto said aqueous iluid;

second conduit means connected to said source of aqueous fluid fordelivering iluid to said refuse;

valve means in said second conduit means for controlling the ow of uidthrough said second conduit means; and

electrical control means responsive to ythe moisture content of saidrefuse for automatically controlling the degree of closure of said valvewhereby lthe moisture content of refuse entering said cell means may bemaintained in a predetermined range.

15. The improvement claimed in claim 14 wherein said second conduitmeans extends over said refuse at a point upstream from the dischargeend of -said pulverizing and grinding means whereby aqueous lluidintroduced to said refuse from said conduit means may be thoroughlymixed with said refuse in said pulverizing and grinding means.

16. The improvement claimed in claim 14 wherein said electrical controlmeans includes electrode means for sensing Ithe moisture content ofrefuse entering said cell means.

17. The improvement claimed in claim 14 wherein said source of aqueousiluid comprises a tank containing an aqueous inoculum enriched inbacteria operative in said bacterial decomposition.

18. The improvement claimed in claim 14 wherein said electrical controlmeans comprises:

a pair of electrodes positioned at the entrance `to said cell means inspaced-apart relation and in contact with said refuse for sensing themoisture content of said refuse; and

means connected between said electrodes and said valve means for openingsaid valve when the moisture content of said refuse reaches apreselected minimum value, and for -closingsaid valve when the moisturecontent of said refuse reaches a preselected maximum value. Y

19.111l a system for composting refuse, the simprovement whichcomprises: Y

a pit for receiving theraw refuse dumped from trucks carrying saidrefuse, said pit having side walls and a bottom with one of said sidewalls extending vertically rom the bottom; v

truck apronmeans adjacent the upper edge of said being positioned at adepth below the top of the pit sucient to allow the dumped refuse toturn in falling from a truck to said conveyorl and to cause .the dumpedrefuse to strike said conveyor with kan impactv of-suicient magnitude tobreak open liquid-containing portions of the refuse whereby the freeliquid in `the refuse will drain through said conveyor to the bottom ofthe pit; and

12 a sump inzthe bottom `of the pit positioned to receive the liquiddrained through said conveyor. Y 20. The systemzdenedin claim19whereinsaid con veyor extends upwardly from one .end of fthe pit to remove thedumped refuse from the pit, and characterized further to include a baiepositioned under Ithe upwardly extending portion4 of said conveyor, saidbaie beingfin-` clined vdownwardly into the pit for draining wash waterand liquid dripping from .the upwardly extending portion.`

of the conveyor into the pit and sump.

21. The system defined in claim 1,9 wherein said con-` veyor extendsupwardly from the pit at an `angle to the horizontal of yabouttwenty-threedegrees, whereby maxi-` mum liquid drainage -from therefuseV is obtained without permitting solid refuse tto slide down saidvconveyor toward the pit.

I a References CitedV the Examiner: 'v UNITED STATES PATENTS 1,535,0394/1925 Ret-tler 198-58 X 2,285,834 6/1942 Proctor 711-9 2,852,7210 9/1958 Posey etal; 324-65 2,929,688 3/ 1960 Riker et al. a 23259.1

MORRIS O. WOLK, Primary Examiner. DELBERT E.y GANTZ, Examiner. i

1. IN A SYSTEM FOR COMPOSTING REFUSE, THE IMPROVEMENT WHICH COMPRISES: APIT FOR RECEIVING RAW REFUSE; REFUSE RECEIVING MEANS ELEVATED ABOVEGROUND LEVEL AND SPACED HORIZONTALLY FROM SAID PIT; A SLATTED CONVEYOREXTENDING ACROSS THE BOTTOM OF SAID PIT AND UPWARDLY TO SAID ELEVATEDREFUSE RECEIVING MEANS; DRAIN MEANS UNDER SAID CONVEYOR; A SUMP IN THEBOTTOM OF SAID PIT BELOW SAID SLATTED CONVEYOR; LIQUID DELIVERY PIPESPOSITIONED UNDER SAID CONVEYOR BETWEEN SAID PIT AND REFUSE RECEIVINGMEANS FOR WASHING INTO SAID SUMP VIA SAID DRAIN MEANS LIQUID AND SOLIDMATERIALS FALLING THROUGH THE SLATS OF SAID CONVEYOR; A STORAGE TANKCONNECTED TO SAID SUMP FOR RECEIVING THE WASHINGS FLOWING INTO SAIDSUMP; A CONDUIT COMMUNICATING WITH SAID STORAGE TANK AND EXTENDING OVERTHE PATH OF REFUSE DISCHARGED FROM SAID REFUSE RECEIVING MEANS; ANDVALVE MEANS IN SAID CONDUIT FOR CONTROLLING THE FLOW OF MATERIAL FROMSAID STORAGE TANK TO SAID REFUSE WHEREBY THE MOISTURE CONTENT OF SAIDREFUSE MAY BE REGULATED AS DESIRED PRIOR TO COMPOSTING THE REFUSE BYBACTERIAL DECOMPOSITION.